1. Field of the Invention
The present invention is related generally to percutaneous entry needles and more particularly to a needle particularly adapted for use in digital subtraction angiography procedures.
2. Description of the Prior Art
In digital subtraction angiography (DSA) the radiologist can make angiograms without the need to selectively place a catheter. The X-ray contrast opaque liquid is injected into the cardiovascular system anywhere that is convenient and relatively safe. Typically, the radiologist might use a vessel in the arm similar to an IV injection site. However, unlike an IV, where the infusion is made through a needle, the needle is replaced by the Seldinger technique with a small bore short catheter. The contrast material is then injected into the vein through this catheter.
The Seldinger technique involves the use of a wire guide such as the one illustrated in Cook U.S. Pat. No. 3,547,103, and also involves a needle and a catheter. The needle is inserted through the skin into the blood vessel. The coil spring wire guide is then threaded through the lumen of the needle into the blood vessel. The needle is then removed from the blood vessel by moving it over the wire guide and unthreading it from the wire guide while holding the wire guide in position in the blood vessel. The catheter is then threaded onto the wire guide and moved into the blood vessel over the wire guide. The wire guide is then removed from the catheter and the blood vessel leaving the catheter in the blood vessel.
The current needle design commonly used for IV infusions and DSA procedures is a long bevelled needle with two flexible wings attached to the proximal end of the needle. Also attached to the proximal end of the needle is flexible tubing with a luer lock provided at the distal end thereof for coupling to the IV supply. The operator uses such a needle, commonly referred to as a butterfly needle, by folding the wings together on one side giving the operator a means to grasp and insert the needle. When used for an IV, the wings are unfolded and then taped or sutured to the skin to secure the needle in place for the duration of the infusion. When used for DSA, however, the needle is not left in place. It is used to introduce the wire guide and then is removed from the blood vessel. Thus, the wings are not even unfolded.